The only issue with scotchguard is that it may make the exterior a little "shiny" and will decrease the breathability of the jacket slightly. It will not harm the jacket.
I prefer the Nikwax spray on DWR or if you want increased waterproofing (at the cost of lower breathability) you can use the Nikwax tent and gear waterproofer.
Keep in mind that waterproofing the outershell will increase water shedding, and limit absorbtion, but it will not make the jacket waterproof. Waterproofing requires the zip out innerlining. The main reason is that water will make it's way through the seams in the outershell, where the liner is fully seam sealed.
Originally Posted by BoochZilla
We have them in stock and shipping. We can ship same day 90% of the time from Philadelphia or NJ.
We also do free return shipping on size exchanges for all REV'IT!
The Dragon is meant to be 4-season all-condition. Light rain won't be a problem. The shell will come with a DWR (Direct Water Repellent) coating which can be replenished with NikWax as necessary to beef up the watershed properties of the outer shell. The inner Hydratex liner will ensure that any water which makes it to the shell will not make it to the body.
I am not sure about Scotchguarding. My gut is that you will not need it. We will see if Badger chimes in with his 2 cents here. The outer shell is meant to be very durable and easy to clean.
Let me know what else I could offer.